Study chemotherapeutic agents of interest to the Division of Cancer Treatment Program, selected and provided by the Project Officer, for their effects on mouse gastrointestinal epithelium and on transplantable mouse gastrointestinal epithelium and on transplantable mouse mastocytoma, P815X2 in ascites and solid forms. Generate data regarding drug toxicity to the gastrointestinal mucosa as a function of drug dose and dose interval. Generate data regarding drug effects on malignant cells in vivo for ascites, primary solid and metastatic tumors for comparable drug doses and schedules. Perform an integrated analysis of this data to describe drug effects in terms of a "therapeutic ratio" so as to indicate optimal drug doses and schedules.